One technical solution to increase long chain branching in a polymer chain is to introduce an α-ω diene like 1,9 decadiene (DD) that, once incorporated in a chain, can connect two chains together and form a H-type branch. One issue with this technology, however, is to avoid forming gels in the reactor as multiple branch-on-branch networks can be formed with the cross-linking reactions.
EP 0227142A2 discloses polymers of a benzocyclobutene and processes for making them. The end product disclosed in this reference contain randomly distributed benzocyclobutene structures in the styrene end blocks.
The present invention addresses this issue by formation of H-branches via post-reactor processes at temperatures greater than the reactor temperature.